1. Field of the Invention
The present invention relates to an endoscope system including an endoscope and a disposable protection cover for covering the endoscope, and also relates to a disposable protection cover and an endoscope for use in such an endoscope system.
2. Description of the Related Art
An endoscope system has been widely utilized for providing diagnostic and therapeutic indications for coeliac cavities of patients and for internal inspection of mechanical structures. To this end, various kinds of endoscopes have been developed. For example, in order to inspect or treat the oesophagus, stomach and duodenum, upper endoscopes have been utilized. Further, colonoscopes have been developed to examine colons and sigmoidoscopes have been proposed to inspect rectums and sigmoid colons. When the endoscope is used, an insertion portion of the endoscope has to be inserted into a cavity of a patient, so that the outer surface of the insertion section of the endoscope is contaminated with living tissues and liquids. Such a contaminated endoscope can not be successively used for other patients. Therefore, once the endoscope is used to diagnose and/or treat a patient, it is necessary to clean and sterilize the endoscope. Of course, the cleaning of the endoscope requires substantial time and during this cleaning time, it is impossible to perform endoscopic procedures by using this endoscope. In order to mitigate such an idle time, it is necessary to prepare a large number of endoscopes. However, endoscopes are rather expensive, so that it is difficult in practice to prepare a large number of endoscopes, particularly in a small hospital or clinic. Therefore, in almost all hospitals and clinics, in practice, after the endoscope has been used for examining or treating a patient, the endoscope is immediately cleaned. Typically, this cleaning requires several minutes to ten minutes. In order to effect the complete washing and sterilization, the cleaning has to be performed for several tens of minutes.
Further, the endoscope has various channels such as an air channel, a water channel, a suction channel, and a forceps channel which extend along the insertion section from a proximal end to a distal end thereof, and these channels, except the forceps channel, are connected via tubes to respective devices such as an air supply pump, a water supply pump, a water suction pump and an air suction pump. These channels are subjected to contact with living tissues and liquids. However, in order to clean these channels of the endoscope completely, a relatively long time is required. Thus, the endoscope can not be utilized efficiently for the duration of the long cleaning time. In a large hospital or clinic, a large number of endoscopes may be prepared in order to mitigate the problem of cleaning time. However, this solution results in an increase in the operation cost. Further, in small clinics, it is practically impossible to prepare a number of expensive endoscopes.
Moreover, the endoscope might be broken during cleaning and the usable life of the endoscope is liable to be shortened by the cleaning.
In order to avoid the above explained various problems, there has been proposed an endoscope system, in which the endoscope is covered with a disposable protection sheath-like cover having channels formed therein. For instance, U.S. Pat. Nos. 4,721,097, 4,741,326, 4,825,850, 4,869,238, 4,991,564, 4,991,565, 5,050,585 disclose various kinds of disposable protection sheath-like covers having channels formed therein. In U.S. Pat. No. 4,646,722, there is shown an endoscope system in which the endoscope is covered with a protection sheath, while a tube having channels formed therein is inserted into a U-shaped cutout formed in an outer surface of the endoscope along a longitudinal axis thereof. Upon diagnosis, the insertion section of the endoscope is covered with the protection sheath, and after the inspection, the sheath is removed from the insertion section and is then discarded. Therefore, it is no longer necessary to clean the endoscope after every inspection.
In the above mentioned U.S. Patents, the protection sheath-like cover is constructed to cover only the insertion section of the endoscope, but does not cover an operation section of the endoscope. It should be noted that the operation section of the endoscope is handled by doctors and operators, and thus is brought into contact with the living tissues and liquids of a patient. Therefore, in order to remove the contamination of the operation section of the endoscope due to such living tissues and liquids, it is advantageous to cover not only the insertion section, but also the operation section of the endoscope. In European Patent Publication No. 0 349 479 A1, there is disclosed an endoscope system, in which not only the insertion section, but also the operation section of the endoscope are covered with a disposable protection cover. That is to say, the protection cover comprises a sheath-like portion for covering the insertion section of the endoscope and a bag-like portion for covering the operation section, the sheath-like portion and bag-like portion being integrally formed. It has been also proposed to form the sheath-like portion and bag-like portion as separate covers. For instance, in European Patent Publication No. 0 341 719 A1, there is proposed another known endoscope system, in which an insertion section of an endoscope is covered with a disposable protection sheath-like cover and an operation section of the endoscope is covered with a disposable protection bag-like cover which is mated or joined with the protection sheath-like cover in order to prevent contamination through the junction of the sheath-like cover and the bag-like cover.
In order to treat a cavity of a patient body, it has been proposed to arrange a forceps channel within the sheath-like cover into which an endoscope is inserted. In this case, it is desired to close an inlet opening of the forceps channel through which forceps are inserted. However, in the known disposable protection cover, nothing has been proposed regarding the construction of the forceps plug for closing the above-mentioned inlet opening of the forceps channel. The forceps plug may be integrally formed with the protection cover or may be provided separately from the protection cover.
When the forceps plug is provided integrally with the disposable protection cover, even if the forceps plug is deteriorated, damaged or broken during the examination, the forceps plug can not be exchanged with a new one. When the forceps plug is damaged, a liquid passing through the forceps channel might flow from the forceps plug. In order to exchange the damaged forceps plug, it is necessary to remove the endoscope and protection cover from the patient, remove the insertion section of the endoscope from the insertion section cover, and then insert the insertion section into a new protection cover having a new forceps plug. This results in that the examination time is prolonged and the patient is subjected to the undesired operations of removing and inserting the insertion section of the endoscope covered with the protection cover. If a deteriorated forceps plug is used, a liquid containing stains and bloods might be ejected from the forceps plug when the forceps channel is used as the suction channel, so that the operators and the floor of the examination room are contaminated.
As explained above, in the disposable protection cover there are formed a forceps channel, an air supply conduit channel and a water supply conduit channel. These channels are extended within the protection cover. In a lateral cross section of the protection cover, these channels are arranged in a substantially semicircular space and the endoscope is inserted into the remaining substantially semicircular space. It should be noted that the distal end of the insertion section of the endoscope is bent in right and left directions and/or up and down directions by operating one or two angle knobs provided on the operation section of the endoscope. In the known endoscope, the distal end portion of the insertion section is bent in a symmetrical manner with respect to a neutral position. For instance, the distal end of the insertion section can be bent upward and downward by the same angles. When such an insertion section of the endoscope is inserted into the protection cover, the bend angles of the distal end in the upward and downward directions become different from each other. That is to say, if the above mentioned channels are arranged in an upward portion within the protection cover, the upward bend angle becomes smaller than the downward bending angle. Such asymmetry in the bending angle makes the operation of the endoscope difficult. For instance, when the distal end of the endoscope is bent downward, the tip portion of the protection cover might be brought into contact with a cavity wall of the patient to damage the cavity wall.
Further, the conduit channels such as the forceps channel, the air supply channel and the water supply channel formed in the disposable protection cover communicate with an external apparatus including a light source, an air pump, a water pump, a suction pump and a signal processing device. Usually, the conduit channels are formed by flexible tubes and these tubes communicate with the above-mentioned devices. The tubes are extended from the operation section cover to the external apparatus. In this case, in order not to prevent a smooth movement of the operation section of the endoscope, these tubes can not be extended tightly. Therefore, the tubes are liable to be hung loosely and this might cause inconvenience in the operation, particularly when the operation section is covered with the operation section cover and the universal cord is covered with a universal cord cover.
Further, when the tubes are loosely hung, there is a risk that they might be brought into contact with the floor. This causes a serious contamination of the sterilized protection cover. In order to avoid such drawbacks, it is considered to bind these tubes and an assembly of tubes with a sterilized protection tube cover. However, in this case, the assembly of tubes with the protection tube cover is loosely hung and the tubes are moved within the protection tube cover when the operation section is moved during the examination.